I installed spamassassin to use it with evolution. When I boot the system, /etc/init.d/spamassassin starts the 'spamd' daemon, with these flags:
DOPTIONS="-d --pidfile=$PIDFILE"
That makes a spamd which listens on a socket for incoming connections.
However, the spamassassin plugin in evolution is set up to not be able to use such a spamd process by default. In evolution-2.6.1/mail/evolution-mail.schemas.in.in, we see the following:
<schema>
<key>/schemas/apps/evolution/mail/junk/sa/local_only</key>
<default>true</default>
<short>Use only local spam tests.</short>
That default 'true' value means that evolution's spamassassin plugin will only use a spamd process if it was run with the "-l" or "--local" flags. See evolution-2.6.1/plugins/sa-junk-plugin/em-junk-filter.c - there's code which checks for the --local flag:
if (em_junk_sa_local_only && try_system_spamd) {
argv [i++] = "ps ax|grep -v grep|grep -E 'spamd.*(\\-L|\\-\\-local)'|grep -E -v '\\ \\-p\\ |\\ \\-\\-port\\ '";
The upshot of this is that evolution ends up starting its own spamd process, with the --local flag, and I end up with two spamd processes running.
We should decide on a suitable default for both spamassassin and evolution - should spamd run with --local or not? It makes no sense for two spamd daemons to be running.
This can/should be fixed in evolution. I don't see it as a spamassassin bug.